This invention relates to a plastic article provided with a coating which provides the plastic article with an increased melting point and an increased temperature induced plastic flow characteristic; i.e., an increase in the temperature at which the plastic article exhibits plastic flow. More particularly, this invention relates to a thermoplastic article provided with a coating of cured material which provides the thermoplastic article with an increased melting point and an increase in temperature induced plastic flow characteristic, and which thermoplastic article provided with such coating is particularly useful as a color light filter.
This invention further relates to apparatus and processes of manufacturing such plastic articles.
Numerous plastic articles, particularly thermoplastic articles are known to the art which have a melting point and which experience a heat induced plastic flow characteristic. By way of example, and not by way of limitation, thermoplastic color light filters are known to the art for providing a single color of light, upon white light comprised of a plurality of colors of light in the visible light spectrum being transmitted thereto. As is further known to the art, the color of light provided by color light filters is dependent upon the color of the light filter. Such color light filters are widely used in the entertainment field, such as for example, in stage theaters, outdoor shows and other applications where relatively bright colored light is desired or required. By way of further example, a typical color light filter includes a transparent, or at least substantially transparent plastic base material, such as for example a thermoplastic material such as polycarbonate, and which has either or both of its outer surfaces suitably coating with a colored dye or which can have colored dye defused into either or both of its outer surfaces. Alternatively, the colored dye can be dispersed throughout the thermoplastic base material. Upon such dye being, for example, a red dye, the color light filter will be a red color light filter and will produce red light upon white light being transmitted to the red color light filter. The red color light filter will permit only red light to pass therethrough and the red color dye will block or absorb all other colors in the white light and prevent them from passing through the red color light filter.
As is further known to the art, and by way of further example, the red color light filter in absorbing the other light colors will become heated and can become sufficiently heated to reach the melting point of the thermoplastic material, causing the color light filter to be destroyed. Further, as is known, as the colored light filter becomes increasingly heated the thermoplastic material, will experience a heat induced plastic flow characteristic which can distort the shape of the filter thereby distorting the colored light produced by the color light filter, such heat induced plastic flow characteristic can ultimately cause the filter to be destroyed.
Accordingly, there is a need in the art for a new and improved plastic article which is provided with an increased melting point and an increased temperature induced plastic flow characteristic and which plastic article can be used as a color light filter. There is a further need in the art for a process and apparatus for manufacturing such plastic article.